If your civ has a planet quality bonus and you choose neutrality your planet's quality will be displayed correclty but you will have unlocked tiles as if you did not have that civilization bonus. (EX, +10% to planet quality on custom civ which gets neutrality, the level 11 (10+1) home planet will now display level 15, but will only have 14 build slots!)
If you purchase orbital terraformers (I actually selected an occupied location, clicked on orbital formers, and clicked on buy..) then all the tiles on your planets are instantly terraformed... but! the listed planet quality does NOT change (eg, a planet quality 10 might end up staying as quality 10, but having 14 build slots).
Also, orbital formers are practically useless in most galaxy sizes (wasting a slot) and the neutrality bonus of unlocked all locations is often underused. Perhaps orbital formers should increase by 1 the max planet quality (and decreasing terraforming cost) while the neutrality bonus do the same.